﻿using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;

namespace Gildor.SwapWin.Shell
{
    static class WinAPI
    {
        [DllImport("user32.dll")]
        public static extern IntPtr WindowFromPoint(Point point);

        [DllImport("user32.dll")]
        public static extern bool GetCursorPos(ref Point lpPoint);

        [DllImport("user32.dll", SetLastError = true)]
        public static extern uint GetWindowThreadProcessId(IntPtr hWnd, out int lpdwProcessId);

        public static Process GetProcessByWindow(IntPtr hWnd)
        {
            int processId;
            GetWindowThreadProcessId(hWnd, out processId);
            return Process.GetProcessById(processId);
        }

        [DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
        private static extern int GetWindowTextLength(IntPtr hWnd);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern int GetWindowText(IntPtr hWnd, StringBuilder lpString, int nMaxCount);

        public static string GetWindowText(IntPtr hWnd)
        {
            // Allocate correct string length first
            int length = GetWindowTextLength(hWnd);
            var sb = new StringBuilder(length + 1);
            GetWindowText(hWnd, sb, sb.Capacity);
            return sb.ToString();
        }

        [DllImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool SetWindowPos(IntPtr hWnd, IntPtr hWndInsertAfter, int X, int Y, int cx, int cy, SetWindowPosFlags uFlags);

        public static readonly IntPtr HWND_TOPMOST = new IntPtr(-1);
        public static readonly IntPtr HWND_NOTOPMOST = new IntPtr(-2);
        public static readonly IntPtr HWND_TOP = new IntPtr(0);
        public static readonly IntPtr HWND_BOTTOM = new IntPtr(1);

        [Flags]
        public enum SetWindowPosFlags : uint
        {
            /// <summary>If the calling thread and the thread that owns the window are attached to different input queues, 
            /// the system posts the request to the thread that owns the window. This prevents the calling thread from 
            /// blocking its execution while other threads process the request.</summary>
            /// <remarks>SWP_ASYNCWINDOWPOS</remarks>
            SynchronousWindowPosition = 0x4000,
            /// <summary>Prevents generation of the WM_SYNCPAINT message.</summary>
            /// <remarks>SWP_DEFERERASE</remarks>
            DeferErase = 0x2000,
            /// <summary>Draws a frame (defined in the window's class description) around the window.</summary>
            /// <remarks>SWP_DRAWFRAME</remarks>
            DrawFrame = 0x0020,
            /// <summary>Applies new frame styles set using the SetWindowLong function. Sends a WM_NCCALCSIZE message to 
            /// the window, even if the window's size is not being changed. If this flag is not specified, WM_NCCALCSIZE 
            /// is sent only when the window's size is being changed.</summary>
            /// <remarks>SWP_FRAMECHANGED</remarks>
            FrameChanged = 0x0020,
            /// <summary>Hides the window.</summary>
            /// <remarks>SWP_HIDEWINDOW</remarks>
            HideWindow = 0x0080,
            /// <summary>Does not activate the window. If this flag is not set, the window is activated and moved to the 
            /// top of either the topmost or non-topmost group (depending on the setting of the hWndInsertAfter 
            /// parameter).</summary>
            /// <remarks>SWP_NOACTIVATE</remarks>
            DoNotActivate = 0x0010,
            /// <summary>Discards the entire contents of the client area. If this flag is not specified, the valid 
            /// contents of the client area are saved and copied back into the client area after the window is sized or 
            /// repositioned.</summary>
            /// <remarks>SWP_NOCOPYBITS</remarks>
            DoNotCopyBits = 0x0100,
            /// <summary>Retains the current position (ignores X and Y parameters).</summary>
            /// <remarks>SWP_NOMOVE</remarks>
            IgnoreMove = 0x0002,
            /// <summary>Does not change the owner window's position in the Z order.</summary>
            /// <remarks>SWP_NOOWNERZORDER</remarks>
            DoNotChangeOwnerZOrder = 0x0200,
            /// <summary>Does not redraw changes. If this flag is set, no repainting of any kind occurs. This applies to 
            /// the client area, the nonclient area (including the title bar and scroll bars), and any part of the parent 
            /// window uncovered as a result of the window being moved. When this flag is set, the application must 
            /// explicitly invalidate or redraw any parts of the window and parent window that need redrawing.</summary>
            /// <remarks>SWP_NOREDRAW</remarks>
            DoNotRedraw = 0x0008,
            /// <summary>Same as the SWP_NOOWNERZORDER flag.</summary>
            /// <remarks>SWP_NOREPOSITION</remarks>
            DoNotReposition = 0x0200,
            /// <summary>Prevents the window from receiving the WM_WINDOWPOSCHANGING message.</summary>
            /// <remarks>SWP_NOSENDCHANGING</remarks>
            DoNotSendChangingEvent = 0x0400,
            /// <summary>Retains the current size (ignores the cx and cy parameters).</summary>
            /// <remarks>SWP_NOSIZE</remarks>
            IgnoreResize = 0x0001,
            /// <summary>Retains the current Z order (ignores the hWndInsertAfter parameter).</summary>
            /// <remarks>SWP_NOZORDER</remarks>
            IgnoreZOrder = 0x0004,
            /// <summary>Displays the window.</summary>
            /// <remarks>SWP_SHOWWINDOW</remarks>
            ShowWindow = 0x0040,
        }

        [DllImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool GetWindowRect(HandleRef hwnd, out Rect lpRect);

        public static Rect GetWindowRect(IntPtr hWnd)
        {
            Rect rect;
            if(!GetWindowRect(new System.Runtime.InteropServices.HandleRef(null, hWnd), out rect))
            {
                throw new Win32Exception();
            }
            return rect;
        }

        [StructLayout(LayoutKind.Sequential)]
        public struct Rect
        {
            private int _Left;
            private int _Top;
            private int _Right;
            private int _Bottom;

            public Rect(Rectangle rectangle)
                : this(rectangle.Left, rectangle.Top, rectangle.Right, rectangle.Bottom)
            {
            }
            public Rect(int left, int top, int right, int bottom)
            {
                _Left = left;
                _Top = top;
                _Right = right;
                _Bottom = bottom;
            }

            public int X
            {
                get { return _Left; }
                set { _Left = value; }
            }
            public int Y
            {
                get { return _Top; }
                set { _Top = value; }
            }
            public int Left
            {
                get { return _Left; }
                set { _Left = value; }
            }
            public int Top
            {
                get { return _Top; }
                set { _Top = value; }
            }
            public int Right
            {
                get { return _Right; }
                set { _Right = value; }
            }
            public int Bottom
            {
                get { return _Bottom; }
                set { _Bottom = value; }
            }
            public int Height
            {
                get { return _Bottom - _Top; }
                set { _Bottom = value - _Top; }
            }
            public int Width
            {
                get { return _Right - _Left; }
                set { _Right = value + _Left; }
            }
            public Point Location
            {
                get { return new Point(Left, Top); }
                set
                {
                    _Left = value.X;
                    _Top = value.Y;
                }
            }
            public Size Size
            {
                get { return new Size(Width, Height); }
                set
                {
                    _Right = value.Width + _Left;
                    _Bottom = value.Height + _Top;
                }
            }

            public static implicit operator Rectangle(Rect rectangle)
            {
                return new Rectangle(rectangle.Left, rectangle.Top, rectangle.Width, rectangle.Height);
            }
            public static implicit operator Rect(Rectangle rectangle)
            {
                return new Rect(rectangle.Left, rectangle.Top, rectangle.Right, rectangle.Bottom);
            }
            public static bool operator ==(Rect rectangle1, Rect rectangle2)
            {
                return rectangle1.Equals(rectangle2);
            }
            public static bool operator !=(Rect rectangle1, Rect rectangle2)
            {
                return !rectangle1.Equals(rectangle2);
            }

            public override string ToString()
            {
                return "{Left: " + _Left + "; " + "Top: " + _Top + "; Right: " + _Right + "; Bottom: " + _Bottom + "}";
            }

            public override int GetHashCode()
            {
                return ToString().GetHashCode();
            }

            public bool Equals(Rect Rectangle)
            {
                return Rectangle.Left == _Left && Rectangle.Top == _Top && Rectangle.Right == _Right && Rectangle.Bottom == _Bottom;
            }

            public override bool Equals(object Object)
            {
                if(Object is Rect)
                {
                    return Equals((Rect)Object);
                }
                else if(Object is Rectangle)
                {
                    return Equals(new Rect((Rectangle)Object));
                }

                return false;
            }
        }

        [DllImport("user32.dll", ExactSpelling = true)]
        public static extern IntPtr GetAncestor(IntPtr hwnd, GetAncestor_Flags gaFlags);

        public enum GetAncestor_Flags
        {
            GetParent = 1,
            GetRoot = 2,
            GetRootOwner = 3
        }

        [DllImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        public static extern bool SetForegroundWindow(IntPtr hWnd);
    }
}
